Reel brake device for tape recorder

ABSTRACT

A brake device used with tape recorders or the like of this invention includes a first brake member acting in the cut-in direction and a second brake member acting in the escape direction, the first and second brake members being disposed adjacent to braked members provided on the take-up and supply sides, respectively. Two brake members are selectively operable so that the selected brake member may act solely in the escape direction irrespective of the rotational direction of the braked members, whereby brake force can be exerted solely in the escape direction without erroneously breaking or severing a tape or the like running between the supply and take-up sides.

United States Patent Goshima et a].

[ 51 June 20, 1972 [54] REEL BRAKE DEVICE FOR TAPE RECORDER [2|] Appl.No; 71,866

[22] Filed:

[30] Foreign Application Priority Data Sept. 26, 1969 Japan ..44 917s3[56] References Cited UNITED STATES PATENTS 2,898,055 8/l959 Genning etal ..242/204 Primary Emminer-Leonard D. Christian Almmeyward,McElhannon. Brooks & Fitzpatrick [57] ABSTRACT A brake device used withtape recorders or the like of this invention includes a first brakemember acting in the cut-in direction and a second brake member actingin the escape direction, the first and second brake members beingdisposed adjacent to braked members provided on the take-up and supplysides, respectively. Two brake members are selectively operable so thatthe selected brake member may act solely in the escape directionirrespective of the rotational direction of the braked members, wherebybrake force can be exerted solely in the escape direction withouterroneously breaking or severing a tape or the like running between thesupply and take-up sides.

13 Claims, 18 Drawing Figures PATENTEDaunzo I972 SHEET 1 [IF 9 FIG. 2A

PATEI-ITEnJum m2 8.670.992

sum 2 BF 9 FIG. 2B

GRAPH OF gggJATION GRAPH OF EQUATION (4) BRAKING FORCE F 1; CICOEFFICIENT OF FRICTION ,u.

FIG. 3

,PATEmEnJum 1972 v 3,670,992 saw 50F 9 PATI-IiHEnJum m2 SHEET 6 BF 9IIIIEI-ITEIJJUIIZO m2 3,670,992

sum 7 [IF 9 FIG. l2

LU Law (D liaw Y Z Fl O O COEFFICIENT OF FRICTION REEL BRAKE DEVICE FORTAPE RECORDER BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION Thisinvention generally relates to a brake device, and more particularly toa reel brake device for tape recorders or the like. 1

2. DESCRIPTION OF THE PRIOR ART In the brake devices heretofore usedwith tape recorders, it has been required that brake force be greaterfor a supply reel than for a take-up reel so as to prevent the tape fromslackening between the two reels during the braking operation. To solvesuch a requirement, various brake devices have been proposed which canprovide a differential brake force in accordance with the direction ofmovement of the tape.

In the known brake device, as will be fully described later, brake shoesare urged into contact with the circumferences of corresponding brakedwheels integral with reel beds so as to brake the wheels with the aid ofthe friction produced between the shoes and wheels. The frictionproviding a brake force is selected to be different in magnitude betweenthe take-up and supply sides, to thereby eliminate any possible slack ofa tape running between the take-up and supply reels. Means used forproviding such differential friction for the brake shoes is generally ofthe following type.

Such means is most often arranged so that the brake shoe cooperatingwith the braked wheel connected to the supply reel is urged into contactwith that wheel in the cut-in direction" while the other brake shoecooperating with the braked wheel connected to the take-up reel is urgedinto contact with that wheel in the escape direction", whereby adifference in brake force may be provided between the two braked wheels.The cut-in direction" referred to above is the direction in which someof the frictional force derived from the contact between a brake shoeand a braked wheel causes the brake shoe to cut into" the braked wheel,and the escape direction" means the direction in which some of thefriction force causes the brake shoe to escape" or go away from thebraked wheel. The brake force exerted in the cut-in direction on thebraked wheel by the brake shoe is much greater than that exerted in theescape direction, and this difference in the magnitude of the brakeforce is provided between the take-up and supply sides.

However, in the known brake device wherein the brake shoe on the take-upside brakes in the escape direction and that on the supply side brakesin the cut-in direction, dust or similar foreign particles accumulatedon the brake shoes or aging of the brake shoes may vary the frictioncoefficient of the brake shoes to provide an extremely increased brakeforce which would result in the so-called bite" effect of the brake shoeon the supply side, and thus that brake shoe exerts too great a breakforce which would sever the tape or the like running between the supplyand take-up sides.

SUMMARY OF THE INVENTION It is an object of the present invention toeliminate the described disadvantages encountered by the prior art brakedevices.

It is another object of the present invention to provide a brake devicewith which brake force can be exerted only in the escape direction.

It is still another object of the present invention to provide a brakedevice which comprises a first brake member acting in the cut-indirection and a second brake member acting in the escape direction, thefirst and second brake members being disposed adjacent to braked membersprovided on the take-up and supply sides, respectively, and beingselectively operable so that the selected brake member may act solely inthe escape direction irrespective of the direction in which the brakedmembers are rotated.

These and other objects and features of the present invention willbecome fully apparent from the following illustrative description takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view of abrake device according to the prior art.

FIG. 2A is a schematic plan view for illustrating the operatingprinciple of the brake shoe and braked wheel in the brake device of FIG.1.

FIG. 2B is a graph illustrating the relation of the friction coefficientbetween the brake shoe and braked wheel of FIG. 2A and the brake forceprovided by the friction.

FIG. 3 is a view which illustrates the construction of a brake deviceaccording to the present invention.

FIGS. 4 and 5 are plan views for illustrating the manner in which thebrake device of FIG. 3 is operated.

FIGS. 6 and 7 are views which illustrate a modified form of the brakearms and the operation thereof.

FIG. 8 is a view which shows another arrangement forthe brake deviceaccording to the present invention.

FIGS. Q and 10 are plan views for illustrating the manner in which thedeviceof FIG. 8 is operated.

' FIGS. ll, 12 and 13 are views which illustrate the operating principleof the brake device shown in FIG. 8.

FIGS. 14 and 15 are views which show a modified form of the brake amused with the device of,FIG..8.

FIGS. 16 and 17 are views which show another form of the brake arm. 1

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before discussing the presentinvention, description will first be made of the problems encountered bythe prior art brake device shown in FIGS. 1 and 2.

Referring to FIG. I, the known brake device comprises a pair of L-shapedbrake levers 1A and IB, brake shoes 2A and 28 formed of felt, rubber orsimilar material and attached to the brake levers l substantiallycentrally of one arm thereof, pivot pins 3A and 3B for pivotallymounting the brake levers 1A and 1B, and braked wheels 4A and 4B whichare braked by the brake shoes 2A and 2B when the latter are urged intocontact with the circumferential edges of the former. Letter arepresents the vertical distance from the pivot pin 3A or 38 to thetangential line passing the point of contact 5 or 5 between the brakeshoe 2A or 2B and the braked wheel 4A or 48. Letter I represents thehorizontal distance between the pivot pin 3A or 3B and the point ofcontact 5 or 5,.An actuator member 6 is provided to impart a verticalforce W to the brake levers 1A and 1B, which are thereby provided with avertical brake force W. Letter L represents the horizontal distancebetween the vertical line passing the pivot pin 3A or 3B and the linealong which the vertical brake force W is imparted. The braked wheels 4Aand 4B are respectively provided with concentric take-up and supply reelbeds as indicated by imaginary circles, and reels 7 and 8 carrying atape T thereon are mounted on these reel beds.

Operation of the above-described arrangement will now be described. Itis assumed that the reel 7 supplies the tape and the reel 8 takes up thetape, that is, the tape is supplied from the reel 7 in the directionindicated by an arrow D and taken up by the reel 8. If a brake force Wis imparted to the brake levers 1A and 13 after the tape T is taken upon the reel 8, then the levers 1A and 18 will be turned clockwise andcounter-clockwise respectively so that the brake shoes 2A and 2B thereonare urged into contact with the respective braked wheels 4A and 4B. Thetransmission of the brake force from Y the brake shoes 2A, 28 to thebrake wheels 4A, 48 will be described hereunder by reference to FIGS. 2Aand 2B.

When brake force W is exerted upon the brake shoe 4A to thereby urge theshoe against the braked wheel 4A, which is then rotating in theclockwise direction, the brake shoe 2A will receive a force uPn from thebraked wheel 4A, where Pn is the vertical reaction of the braked wheel4A and p. is the friction coefficient between the brake shoe 2A and thewheel 4A.

In this case, the equilibrium of the moment about the pivot pin 3A maybe expressed as:

artPn LW= IPn For the other braked wheel 43 which is also rotating inthe clockwise direction, the vertical reaction Pn' imparted therefrom tothe brake shoe 28 can be derived in the similar manner:

The brake force is the result of the vertical reaction Pn or Pn'multiplied by the friction coefficient a, and the direction of the brakeforce is opposite to the direction in which the braked wheels 4A and 4Bare rotated. Thus, when the braked wheel 4A is rotating clockwise, thebrake force F therefor is expressed as:

F=p.Pn=y.LW/(la J.) (3) and when the braked wheel 48 is rotatingclockwise, the brake force F therefore is expressed thus:

If these equations 3 and 4 are graphically represented with the frictioncoefficient as the abscissa and the brake force as the ordinate, thenthe equation 3 will take the form of a rectangular hyperbola in which p.l/a and F LW/a are asymptote, as shown in FIG. 2B, which shows only afirst quadrant of the graph. In FIG. 2B, the curve representing theequation 3 shows the variation arising in the brake force F with thevariation in the coefficient of friction p. between the brake shoe 2Aand the braked wheel 4A during the braking in the cut-in direction,while the curve representing the equation 4 shows the similar relationbetween the brake shoe 2B and the braked wheel 48 during the braking inthe escape direction. As will be seen from the curve for the equation 3,the brake force F will be greatly varied for a minute variation in thefriction coefficient p. when the brake is actuated in the cut-indirection. Such a great variation in the brake force, together with anincreased friction coefficient resulting from accumulation of dust orother foreign matters between the brake shoe and the braked wheel, wouldincrease the brake force to such an abnormally great degree that may becalled a bite effect, and as a result the supply reel 7 is subjected toan extremely great brake force which might sever the tape.

The present invention seeks to prevent the occurrence of such bite"effect, and for this purpose the brake device of the present inventionis so arranged that the brake force is exerted only in the escapedirection irrespective of the rotational direction of the braked wheels,as shown by the curve for the equation 4 in FIG. 2B.

Referring now to FIGS. 3 to 5, there is shown an example of the brakedevice constructed according to the present invention. In FIG. 3, thereis provided a pair of brake arms 11A and 12A having brake shoes of felt13A and 14A attached thereto at one end. The brake arms 1 1A and 12A atthe other end are pivotally connected through pins 15A and 16A to a pairof holding levers 17A and 18A, respectively, which are pivotally mountedon pivot pins 19A and 20A. Springs 21A and 22A secured at one end to abase plate (not shown) are connected at the other end to the brake arms11A and 12A so as to urge the brake shoes on the brake arms into contactwith the circumference of a braked wheel 23A.

It should be noted that the brake arms 11A and 12A are crooked toprovide sloped surfaces 11A and 12A respectively, and in opposedrelationship with these sloped surfaces there are provided pins 24A and25A fixed to the base plate to guide the movement of the brake arms.Stopper pins 26A and 27A are provided on the base plate to stop theholding levers 17A and 18A respectively. A brake release member 28A isprovided to rotate the brake arms 11A and 12A against the force of thesprings 21A and 22A to thereby bring the brake shoes 13A and 14A out ofengagement with the braked wheel 23A.

Members indicated by 118 to 278 are similar to the described members 11Ato 27A, and thus the members 11A, 118 to 27A, 27B and 28 togetherconstitute an entire brake device.

A pair of reels 30 and 31 having a tape T wound thereon are mounted onunshown reel beds provided on the braked wheels 23A and 238. The springs21A and 22A connected to the brake arms 11A and 12A are greater inspring force than the springs 21B and 22B connected to the brake arms11!! and 128, respectively.

In the device of FIG. 3, when the reels 30 and 31 are rotatingcounter-clockwise to transport the tape T from the reel 30 to the reel31, if the brake release members 28 are released to displace in thedirection E, the brake arms 11A, 12A and 11B, 12B are pulled by theassociated springs 21A, 22A and 21B, 22B so that the brake shoes 13A,14A and 13B, 14B are urged into contact with the braked wheels 23A and23B respectively. Thus, the braked wheels 23A and 23B are subjected to abrake force.

At the same time, the brake arms 11A, 12A and 11B, 12B are displacedleftwardly as viewed in FIG. 3 due to the friction between the brakeshoes and the braked wheels. Such leftward displacement of the brakearms 11A, 12A is shown in FIGS. 4 and 5. Upon release of the brakerelease members 28, the brake arms 11A and 12A are displaced leftwardlyfrom the position of FIG. 4 to the position of FIG. 5 due to thefriction between the brake shoes 13A, 14A and the braked wheel 23A.Thus, the sloped surface 11A of the arm 11A is leftwardly guided by thefixed pin 24A, to swing the holding lever 17A counter-clockwise aboutthe pin 19A, so that the brake shoe 13A is raised from the brake wheelagainst the force of the spring 21A and accordingly the brake arms 11Ais moved until the component of the friction force of the shoe 13A whichis along the sloped surface 11A is balanced with the component of theresiliency of the spring 21A which is along the sloped surface 11A. Forthis reason, the brake force of the brake shoe 13A can be made verysmall by arranging the spring 21A so as to provide a smaller componentof resiliency along the sloped surface 1 1A.

As shown in FIG. 5, the other brake arm 12A is also moved leftwardlyuntil the holding lever 18A is stopped by the pin 27A. Thus, the slopedsurface 12A of the brake arm 12A is disengaged from the pin 25A to allowthe brake shoe 14A to be urged against the braked wheel 23A by thespring 22A to thereby brake the wheel 23A. Thus, the braked wheel 23A isbraked chiefly by the brake shoe 14A. 7

The braking operation described just above is also the case with theother braked wheel 238, which is braked chiefly by the brake shoe 143 inthe similar manner.

When braked, the braked wheel 23A is subjected to a greater brake forcethan the other wheel 238 because the spring 22A has a greater springforce than the spring 228 as mentioned previously. As a result, the tapeT is maintained taut without any slack during the braking operation. Inaddition, .both brake shoes 14A and 14B brake the respective brakedwheels 23A and 23B always in the escape direction, and this entirelyeliminates the undesirable possibility that the tape may be adverselyaffected by the displacement of the brake shoes.

In case where the braked wheels 23A and 23B are rotating in the oppositeor clockwise direction to take up the tape T on the reel 30, the mainbraking role is played by the brake shoes 13A and 138, while the brakeshoes 14A and 14B are now almost idle in the same way as the shoes 13Aand 138 were in the preceding case.

FIGS. 6 and 7 show a modified form of the brake device although onlyone-half thereof is shown to explain the relation between the brakedwheel and the brake arms. This modified form differs from the previousembodiment in that brake arms 11 1A and 112A spring-loaded by springs121A and 122A play the opposite roles to the above-described brake arms11A and 12A of FIG. 3. More particularly, when the braked wheel 123A isrotating counter-clockwise, for example, if the brake release member128A is released, then the brake arm 112A acts in the cut-in directionwhile the brakearm 111A brakes in the escape direction. This is becausethe sloped surface 112A of the brake arm 112A is guided by the fixed pin125A and the arm 1 12A is moved due to the friction between the brakeshoe 114A and the braked wheel 123A until the component of thefrictional force of the braked wheel 123A which is along the slopedsurface 112A is balanced with the component of the resiliency of thespring 122A which is along the sloped surface 112A. Thus, the brake arm112A remains almost idle, whereas the other brake arm 111A acts to brakethe wheel 123A in the escape direction with the aid of the spring 121A.The above-described operation also holds true of an unshown half of thebrake device, in which a brake arm 111B (not shown) brakes a brakedwheel 123B (not shown) in the escape direction.

FIGS. 8 to show a further embodiment of the present invention, in whicha pair of unitary brake arms have a single brake shoe corresponding toeach braked wheel, although FIGS. 9 and 10 only show a half of suchdevice. As shown in FIG. 8, unitary brake arms 301A and 3018 arebifurcated, and single brake shoes 302A and 3028 are attached to therespective brake arms substantially centrally of the bridge portionsthereof. The brake arms 301A and 301B have pins 303A, 304A and 303B,304B studded at the ends of the leg portions thereof. Holding levers305A and 3058 for holding the brake arms 301A and 301B are pivotallymounted on mount plates 306A and 3068 by means of pins 307A and 3078,respectively (FIGS. 9 and 10). The holding levers 305A and 3058 areformed with slots 308A and 3088 for slidably receiving therein the pins303A and 3033 studded in the brake arms 301A and 301B.

Holding levers 309A and 309B are pivotally mounted on mount plates 310Aand 3108 by means of pins 311A and 311B, and these levers are formedwith slots 312A and 312B. Brake springs 313A and 3138 are connected tothe base plate and to brake arms 301A, 3013. Wires 314A and 314B connectthe brake springs 313A and 313B to a brake release member 314. Stopperpins 315A, 316A and 315B, 316B are provided on the base plate in opposedrelationship with the inner ends of the holding levers 309A, 305A and309B, 305B. Braked wheels 317A and 317B have reel beds on which arelaced reels 318A and 318B having a magnetic tape T wound thereon.

With this arrangement, the brake release member 314 is normally urged inthe direction a against the force of springs 313A and 313B, so that thebrake shoes 302A and 302B on the brake arms 301A and 3018 are maintainedout of engagement with the braked wheels 317A and 31713. When the brakedwheels 317A and 317B are rotating in the counterclockwise direction totake up the magnetic tape T from the reel 317A onto the reel 317B, ifthe brake release member 314 is released in the direction opposite tothe direction a, then the brake arms 301A and 301B will be pulled by thesprings 313A and 31313 to urge the brake shoes 312A and 302B intoengagement with the respective braked wheels 317A and 3178. Thus, thebraked wheel 317A displaces the brake shoe 302A against the force of thespring 313A from the position of FIG. 9 in the direction b shown in FIG.10, whereby the pin 304A on the brake arm 301A slides in the slot 312Aand the holding lever 309A is rotated clockwise until it is stopped bythe stopper pin 315A. The other brake shoe 3028 is also displacedagainst the force of the spring 313B by the braked wheel 317B in thesame direction b, so that the pin 3038 on the brake arm 301B slides inthe slot 3083 of the holding lever 3058 from the position of FIG. 8, tothereby rotate the lever 305B in the clockwise direction until the lever3058 is stopped by the stopper pin 316B.

The operating principle of the brake arms 301A and 3018 is illustratedin FIGS. 11 and 12, wherein the braked wheels 317A and 3178 are shown asif they were rotating in opposite directions, but it is assumed thatboth wheels are rotating in one direction 0 (counter-clockwise). Inother words, the wheels 317A and 317B are braked by the brake shoes 302Aand 3028 engaging the wheels in the escape direction.

In FIGS. 11 and 12, a represents the vertical distance from the pointsof contact between the brake shoes 302A, 302B and the braked wheels317A, 3178 to the pivot pins 303A, 3038 of the brake arms 301A, 3018.Suffixed letters I and 1 represent the horizontal distances from thepoints of contact between the brake shoes 302, 302A and the wheels 3178,317A to the respective pivot pins 303B, 303A, and L, and L thehorizontal distances from the lines of the brake force imparted by thesprings 31B, 313A to the vertical line passing the pivot pins 303B,303A.

Where the brake shoes 302A, 3028 are located substantially centrally ofthe brake arms 301A, 3018, the relation that 1 L L 1 will be satisfiedand at the same time, the relation that l 1 and L L will be establishedbecause the points of contact between the brake shoes 301B, 301A and thebraked wheels 317B, 317A are displaced rightwardly as viewed in FIG. 8.Therefore, as shown in FIG. 13, the brake force F, of the braked wheel317B imparted by the brake shoe 3023 is given as F1: l i r W) by theaforesaid equation 4, which means a rectangular hyperbola in which p.=l,/ a

and

F L W/a are asymptote. Similarly, the brake force P of the other brakedwheel 317A imparted by the brake shoe 302A takes the form of arectangular hyperbola in which F L W/a are asymptote. Such rectangularhyperbolas are partly shown in FIG. 13.

It will be seen from FIG. 13 that the brake force F exerted on thebraked wheel 317A is greater than F,, whereby the tape T is maintainedtaut between the reels 318A and 3188. Also, both brake forces F and Fare exerted in the escape direction and this eliminates the previouslydescribed drawbacks.

It will further be noted that the brake device of FIG. 8 achieves thesame result as described above even if the braking operation takes placewhen the braked wheels are rotating in the opposite direction to take upthe tape T onto the reel 318A.

FIGS. 14 and 15 shows a modified form of the brake arm which constitutesa half of the brake device. The brake arm indicated by 431 has a brakeshoe 432 attached thereto substantially centrally thereof, and pins 433and 434 studded at the opposite ends. Connecting levers 435 and 436formed with slots 437 and 438 are connected to the brake arm 431 bymeans of the pins 433 and 434 received in the slots 437 and 438, so thatthe brake arm 431 is axially movable within the limit defined by theslots. The connecting levers 435 and 436 are pivotally connected tofixed mounts 439 and 440, respectively. The brake arm 431 is urgedtoward a braked wheel 442 by a spring 441 so as to bring the brake shoe432 on the brake am into contact with the braked wheel. Stopper pins 443and 444 are provided to restrict the movement of the connecting levers435 and 436. A brake release bar 445 is connected to the brake arm 431.

With this arrangement, when the braked wheel is rotating in thedirection indicated by an arrow 446 in FIG. 15, an exerted force willcause the brake arm 431 to be displaced leftwardly as viewed in thefigure due to the friction between the brake shoe 432 and the brakedwheel 442, whereby the pin 434 strikes the left end of the slot 438 andthe connecting lever 436 strikes the pin 444, thus restricting the pin434. On the other hand, the pin 433 at the left end of the arm 431 movesin the slot 437 approximately to the center thereof and the connectinglever 435 is disengaged from the pin 443, whereby the pin 433 takes anunrestricted position. This means that the braking operation takes placein the escape direction with the pin 434 as the pivot. Similarly, whenthe braked wheel 442 is rotating in the opposite direction to thatindicated by the arrow 446, the brake force will occur in the escapedirection with the opposite pin 433 as the pivot.

FIG. 16 illustrates a further modification of the brake arm used withthe brake device of FIG. 8. The brake arm 447 has a brake shoe 448attached thereto substantially centrally thereof, and pins 449 and 450studded at the opposite ends.

These pins 449 and 450 are loosely received in slots 451' and 452'formed in mount plates 451 and 452.

The brake arm 447 is urged toward a braked wheel 454 by a spring 453 soas to bring the brake shoe 448 on the arm into contact with the brakedwheel. A brake release bar 455 is connected to the brake arm.

In this example, if the braked wheel is rotating in the directionindicated by an arrow 456 in FIG. 17, the brake am 431 will be displacedleftwardly as viewed in the figure, due to the friction between thebrake shoe 448 and the braked wheel 454, whereby the pin 449 strikes theleft end of the slot 451' to thereby restrict the pin 449. The pin 450moves leftwardly in the slot 452' to take an unrestricted position. Thismeans that the brake force takes place in the escape direction with thepin 449 as the pivot. Similarly, the brake force will occur in theescape direction with the pin 450 as the pivot when the braked wheel 454is rotating in the opposite direction to that indieated by the arrow456.

In the various embodiments described above, the brake unit shown in FIG.4 or 9 is provided in a pair to form an entire brake device as shown inFIG. 3 or 8, whereas the brake units constituting the device need not tobe identical and it is of course possible to employ a combination ofdifferent brake units such as those shown in FIGS. 4 and 9 to attain thesame result.

According to the present invention, as described hitherto, the brakeshoes act in the escape direction irrespective of the direction in whichthe braked wheels are rotating, and therefore, the brake force willnever develope to an abnormally great degree even if the coefficient offriction between the brake shoes and the braked wheels should beincreased by aging of the brake shoes or by dust or other foreignparticles accumulating thereon. Furthermore, the ratio and magnitude ofthe braking forces during the reversal of the rotation of the brakedwheels can be set as desired by suitably selecting the points of contactof brake shoes, the pivots about which the brake arms are moved, and theposition for applying pressure to the brake shoes. Thus, there isprovided a highly safe brake device which will never injure or break thetape.

While the present invention has been shown and described as applied toan apparatus for transporting a magnetic tape, it is to be understoodthat the invention may also be applicable to other machines fortransporting strips such as cinefilms, wires, etc.

It is also to be understood that various modifications and changes maybe made without departing from the scope of the present invention whichis restricted only by the appended claims.

What is claimed is:

1. A brake device applied to a reel for taking up a fine stripcomprising a wheel to be braked, at least one brake shoe member to bepress contacted with said wheel when the wheel is braked, at least onebrake shoe retainer for retaining said brake shoe member, said retainerbeing shiftable in the tangential direction of the braked wheel at thecontact point between said brake shoe member and said braked wheel whenthey are operated to be press contacted and thereby the brake shoemember substantially works as an escape direction brake shoe regardlessof the rotational direction of the wheel; and brake operating meanscoupled to said retainer for shifting the retainer to press contact thebrake shoe to the wheel to be braked.

2. A brake device according to claim 1, in which at least one pair ofthe retainers are provided for the wheel and each brake shoe is providedfor each of the retainers, one brake shoe imparts a brake force to thewheel in the escape direction relative to the rotational direction whilethe other brake shoe imparts cut-in direction brake force, and saidbrake operating means has means to move the brake shoe retainer, whichengages with theretainer, when the brake shoe brakes the wheel, so thatthe brake shoe retainer having braking force in the cutin direction ismoved to shift the brake shoe away from the wheel to substantiallyeliminate the braking'force in the cut-in direction so as to brake thewheel by the brake shoe having the braking force in the escapedirection.

3. A brake device according to claim 1, in which said brake shoeretainer has two pivots not becoming effective simultaneously, saidpivots being convertible when the retainer shifts as the brake shoe onthe retainer receives the frictional force from the braked wheel so thatthe brake shoe imparts brake force in the escape direction regardless ofthe rotational direction of the wheel.

4. A brake device according to claim 2, in which said brake shoe movingmeans comprises a cam portion formed on the brake shoe retainer and aguide member contacting with the cam portion, the cam portion having acam to move the retainer having the brake shoe to brake the wheel in thecut-in direction away from the wheel.

5. A brake device according to claim 2, in which said brake operatingmeans has an elastic member I coupled with the brake shoe retainer andmoved to the shoe mounted position to give an elastic force for brakingto the brake shoe.

6. A brake device according to claim 2, in which said brake shoeretainers are symmetrically arranged relative to the wheel, one end ofthe retainer is pivotably fixed and the other end of the retainerprovides with the brake shoe opposed to the wheel and the middle of theretainer provides with a portion cooperative with said retainer movingmeans.

7. A brake device according to claim 1, in which said wheels to bebraked are provided on rotating means for rotating the take up reel andsupply reel, respectively, and brake shoes are moved in the tangentialdirection of the wheel due to the frictional force of the wheel so as togive the wheel the braking force in the escape direction.

8. A brake device according to claim 7, in which at least one pair ofthe brake shoe retainers is provided for each wheel to be braked, onebrake shoe imparting a brake force to the wheel in the escape directionand the other. brake shoe imparting a brake force to the wheel in thecut-in direction, andsaid brake operating means has means to move eachof the brake shoe retainers, which engages with the retainer and thebrake shoe imparting braking force in the cut-in direction is moved byreceiving the frictional force of the wheel when the shoe brakes thewheel so as to move the brake shoe away from the wheel, so that thebrake force of the brake shoe giving the braking force in the cut-indirection is eliminated and the brake force is given to the wheel onlyby the brake shoe giving the braking force.

9. A brake device according to claim 8, in which said retainer movingmeans comprises a cam portion formed on the brake shoe retainer and aguide member contacting with the cam portion, the cam portion beingshaped in such a manner that, when the brake shoe to brake in the cut-indirection shifts by the frictional force of the wheel, the retainer ismoved to the direction out of the tangential line of the brake shoe tomove the brake shoe away from the wheel.

10. A brake device according to claim 8, in which said brake operatingmeans has elastic members coupled with each of the brake shoe retainers,respectively, and the oppression force of the elastic member of thebrake shoe retainer to brake the wheel of the supply reel is larger thanthat of the elastic member of the brake shoe retainer to brake the wheelof the take-up reel, so that the brake force imparted to the wheel ofthe supply side is larger than that imparted to the wheel of the take upside, and the fine strip is braked and stopped without slack between thesupply and take up reels.

1 l. A brake device according to claim 10, in which said elastic membersare coupled to each of the retainer symmetrically with the bisectingvertical line of the line connecting the rotational centers of thewheels, and the brake shoes are provided externally of each of theelastic members.

12. A brake device according to claim 7, in which said each brake shoeretainer is provided for each wheel, and said brake operating means hasat least one elastic member corresponding to each retainer and theelastic member is symmetrically coupled to the brake shoe deviatedposition, and each brake frictional force from the braked wheel so thatthe brake shoe imparts brake force in the escape direction regardless ofthe rotational direction of the wheel and the brake force of the brakeshoe at the supply reel becomes larger than that of the brake shoe atthe take up reel.

* i i i UNITED STATES PATENT OFFICE 569 CERTIFICATE OF CORRECTION PatentNo. 3'67O'992 Dated June 20, 1972 Inventor( TAKESHI GOSHIMA It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Col. 2, line 55, after the word "tape" insert -T-; Col. 3, line 16formula should read F pPn= 1LW/l+a 1)-; Col. 4, line 26, "arms" shouldread -arm-;

Signed and sealed this 31st day of October 1972.

.( SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attestlng Officer Commissionerof Patents

1. A brake device applied to a reel for taking up a fine stripcomprising a wheel to be braked, at least one brake shoe member to bepress contacted with said wheel when the wheel is braked, at least onebrake shoe retainer for retaining said brake shoe member, said retainerbeing shiftable in the tangential direction of the braked wheel at thecontact point between said brake shoe member and said braked wheel whenthey are operated to be press contacted and thereby the brake shoemember substantially works as an escape direction brake shoe regardlessof the rotational direction of the wheel; and brake operating meanscoupled to said retainer for shifting the retainer to press contact thebrake shoe to the wheel to be braked.
 2. A brake device according toclaim 1, in which at least one pair of the retainers are provided forthe wheel and each brake shoe is provided for each of the retainers, onebrake shoe imparts a brake force to the wheel in the escape directionrelative to the rotational direction while the other brake shoe impartscut-in direction brake force, and said brake operating means has meansto move the brake shoe retainer, which engages with the retainer, whenthe brake shoe brakes the wheel, so that the brake shoe retainer havingbraking force in the cut-in direction is moved to shift the brake shoeaway from the wheel to substantially eliminate the braking force in thecut-in direction so as to brake the wheel by the brake shoe having thebraking force in the escape direction.
 3. A brake device according toclaim 1, in which said brake shoe retainer has two pivots not becomingeffective simultaneously, said pivots being convertible when theretainer shifts as the brake shoe on the retainer receives thefrictional force from the braked wheel so that the brake shoe impartsbrake force in the escape direction regardless of the rotationaldirection of the wheel.
 4. A brake device according to claim 2, in whichsaid brake shoe moving means comprises a cam portion formed on the brakeshoe retainer and a guide member contacting with the cam portion, thecam portion having a cam to move the retainer having the brake shoe tobrake the wheel in the cut-in direction away from the wheel.
 5. A brakedevice according to claim 2, in which said brake operating means has anelastic member coupled with the brake shoe retainer and moved to theshoe mounted position to Give an elastic force for braking to the brakeshoe.
 6. A brake device according to claim 2, in which said brake shoeretainers are symmetrically arranged relative to the wheel, one end ofthe retainer is pivotably fixed and the other end of the retainerprovides with the brake shoe opposed to the wheel and the middle of theretainer provides with a portion cooperative with said retainer movingmeans.
 7. A brake device according to claim 1, in which said wheels tobe braked are provided on rotating means for rotating the take up reeland supply reel, respectively, and brake shoes are moved in thetangential direction of the wheel due to the frictional force of thewheel so as to give the wheel the braking force in the escape direction.8. A brake device according to claim 7, in which at least one pair ofthe brake shoe retainers is provided for each wheel to be braked, onebrake shoe imparting a brake force to the wheel in the escape directionand the other brake shoe imparting a brake force to the wheel in thecut-in direction, and said brake operating means has means to move eachof the brake shoe retainers, which engages with the retainer and thebrake shoe imparting braking force in the cut-in direction is moved byreceiving the frictional force of the wheel when the shoe brakes thewheel so as to move the brake shoe away from the wheel, so that thebrake force of the brake shoe giving the braking force in the cut-indirection is eliminated and the brake force is given to the wheel onlyby the brake shoe giving the braking force.
 9. A brake device accordingto claim 8, in which said retainer moving means comprises a cam portionformed on the brake shoe retainer and a guide member contacting with thecam portion, the cam portion being shaped in such a manner that, whenthe brake shoe to brake in the cut-in direction shifts by the frictionalforce of the wheel, the retainer is moved to the direction out of thetangential line of the brake shoe to move the brake shoe away from thewheel.
 10. A brake device according to claim 8, in which said brakeoperating means has elastic members coupled with each of the brake shoeretainers, respectively, and the oppression force of the elastic memberof the brake shoe retainer to brake the wheel of the supply reel islarger than that of the elastic member of the brake shoe retainer tobrake the wheel of the take-up reel, so that the brake force imparted tothe wheel of the supply side is larger than that imparted to the wheelof the take up side, and the fine strip is braked and stopped withoutslack between the supply and take up reels.
 11. A brake device accordingto claim 10, in which said elastic members are coupled to each of theretainer symmetrically with the bisecting vertical line of the lineconnecting the rotational centers of the wheels, and the brake shoes areprovided externally of each of the elastic members.
 12. A brake deviceaccording to claim 7, in which said each brake shoe retainer is providedfor each wheel, and said brake operating means has at least one elasticmember corresponding to each retainer and the elastic member issymmetrically coupled to the brake shoe deviated position, and eachbrake shoe imparts different braking force in the escape direction tothe wheel and the brake force for the supply side becomes larger.
 13. Abrake device according to claim 12, in which said brake shoe retainerhas two pivots not becoming effective simultaneously, said pivots beingconvertible when the retainer shifts as the brake shoe on the retainerreceives the frictional force from the braked wheel so that the brakeshoe imparts brake force in the escape direction regardless of therotational direction of the wheel and the brake force of the brake shoeat the supply reel becomes larger than that of the brake shoe at thetake up reel.